Electric resistance apparatus.



L M. HANKIN. ELECTRIC RESISTANCE APPARATUS. APPLICATION FILED JA.N.5, 1909.

942,555. Patented Dec. 7, 1909.

713271 I I. lnveh UNITED sTATEs PATENT OFFICE- MAX HANKIN, OF BRUSSELS, BELGIUM.

' Specification of ELECTRIC RESISTANCE APPARATUS.

Letter P t n Patented Dec. 7,1909.

Application iuea January 5; 1909. Serial No. 470,782.

Electric heating apparatus are known in which the conducting resistance constituting the heating material is composed of a mixture of particles of metallic substances and insulating substances.

N ow the presentil'ivention is based on the use of materials in the condition of more or less 'fine particles for constituting a resistance to the flow of an electric current. For this purpose there may be employed a mixture of metallic particles and particlesof insulating substances in, proportions varying according to the degree of resistance which it is desired to produce. Or metallic particles only may be used, and more particularly particles of cast iron.

The particles constituting the resisting material are charged into a conducting metal envelop that is entirely closed in which two metal terminals are embedded. Each of the terminals projects through one of the ends of the envelop to effect the entry and exit of the electric current. These terminals are insulated from the parts of the envelop through which they extend, and their ends may be separated from each other by a greater or less distance according to the degreecf resistance which it is desired to produce. I I

One form of apparatus constructed according to this invention is illustrated by way of example in the accompanying drawing in cross section.

The conducting metal envelop is preferably composed of two cups or cylindrical vessels, (1, screwed together and filled with the resisting material, I). A hole, 0, extends through the closed end or bottom of each of the cups a. The terminals, (1, are introduced througn the holes, 0. These holes, 0 are sufficiently large to allow of providing an insulating space between their sides and thetermin -s,

d, when the latter are fixed in .place/by/,

.means of nuts, 0 f and insulating washers, g

of mica or equivalent material. The terminals aL-maybe screwed to a greater or less depth into the resisting material I), the space between their ends being greater than the distance that separates them laterally from the envelop and preferably less than or at most equal to twice the said distance. Part of the electric current passes from one terminal to the envelop and thence to the other terminal and the more the terminals are distant from one 'another the greaterwill be the parb qiff the current which thus passes by the envelop. The resistance-to the passage of thecuriehttmay be diminished by fixing in the envelop-a-supplementary terminal h. by which the current can be taken off after passing only through the resisting material between one terminal and the envelop.

\Vhen atre'sisting material is used consisting of a mixture of metal, particles and insulating particles such a mixture may be advanta eously composed by way of example f: the toll wing substances in the proportions stated: I

Refractory earth 50 partsbywei ht. Plumbago/ 1 7.5

Asbestos/fiber- 1 Granulated cast iron 58.5 4

and lts resistance may be lnereased or d1- minishedby )varying the proportion of the granulated cast iron. As already stated hereinbefore, the-resisting-material may also be constitu ed' by granulated cast iron redueed to particles of moreor less fineness.

For use with a current of low amperage the particles should be finer, and the metal terminals c, should be of smaller cross section than for a current of greater amperage. On the 'otherlhand the internal dimensions of the envelop a, should be increased in direct pro ortion to the current voltage so that the iigher the voltage the greater will be the thickness of the resisting .material which must be traversed bythe current.

The particles are well moistened at first exposure to with water, and then dried b theair-with the object of pro ucing an oxidation of the surface of each metal particle ,in order to increase its resistance to the paS- Marge of the current. Before the particles 'are charged'into the envelop a, Water is 111') @Apparatns constructed in the manneraclcle'dto the particles so as towform a paste which is.tl1-erra'a1n1ned firmly into the envelop. c 5

"The *resi '(lncetl into the envelop immediately after the first atld-itimi of water-without locingal lowed to (try, but in that *ase it' would otter much less resistance to the flow of the current.-

hereinbefore described may be employed in the llltlllllfiltftlllt) of 'rheostats; They are especially: suitable fornse as automatic relsis tiances forstarting motors. llfh'en such 1.3,apparatusare included in an arc lamp cir- 4 Cult; they nsure agreat'constancy iii the intensity of the light, obviatefluctuations, and dnnm'lsh considerably the consumption ct ,current, whilelengthening the "life ole the.

Q0 carbons:

hen used in a glow lamp circult, these apparatus etl'ectlikewise a saw 25'increasesgradually without flickering,

. I" l f1s regulated 1'11 such-a mannerthat a better light is OlJttllhQCt with the same ing of current; they in'iprove the liglt and mcrcasethe etlicient life of the lamps.

' Generally on lightnig the lamps, the. ,hghtl anr voltage'with'a less consumption of ainperes. What Iclann as my mvention and desire 30- to secure by Letters Patent is ing n'iater l filling said envelop and "two 1. In a device for use as a resistance in an electric circuit, in combination, a closed con- "ducung metal envelop, part1cles of a res1ststingmaterial'might be i1'it1'o-,,

BEST AVAILABLE COPY terminals extending 'throng'h andll insrilated from opposite ends of the said envelop and embedded-in the sa id pz rrtieles I 9121; In a (lei?v e for useas. a,

electric circuit, in combination, a closed conclnc tingenetaleni elp g, particles of a resisting material analgesia envelop and two I terminals:extending through and insiilated from opposite ends of the said envelop and embedded in the said particles, thesaitl ter minalsibeing separatecl'from each'othcr by a distaneeef about twice the distance thatseparates. them laterally from the; enyclop. 3. In a devicef use a res" tanec in an electric" 'ci rciii "tlnctin metal casing. particles ofca'st iron 1 lill ingsaitl ca'sing and two terminals entend ing through" and iiisnlatcdg-froiii opp o'ite ends of the'said envelop and enibecl'cled in the said particles. 1 1

t. In a device'for use as-alresistanc'e in an electric circuit, in combination, a-closed conlncting metal easing, rusty particles cast iron filling said rising and two terminals extending through and" insulated from op: osite= e 11'd's "ot -the saitl cas ing andceinbilded inktl'lsaitt'particles. E i

In testimony whereoifi 1"1an'ie to' tl'iis sp'c'cificfatiol 111' l two 'snbscr" gwitnesse havj '1 my be p s hw Qf Witnesses! -I-I 1 v AD Voonnw sistance in an a closed conl 

